Stabilizer pad for vehicles

ABSTRACT

A reversible stabilizer pad for use with stabilizer arms of vehicles. The reversible stabilizer pad has a plate with first and second ground contact faces pivotally coupled to the stabilizer arm such that the plate can rotate about the said arm to engage the ground surface with either ground contact face. A cam is provided to prevent unintentional flipping of the stabilizer pad. In one embodiment, the stabilizer pad is of a two-piece construction to provide improved balance to the pad to prevent unintentional flipping of the pad. In another embodiment, the stabilizer arm includes a resilient plate for contacting the cam over a portion of a predetermined range of rotation of the pad with respect to the arm. In another embodiment, a resilient roller is coupled to one of the pad and the arm to contact the other of the pad and the arm to provide a resistance to rotation of the pad with respect to the arm.

This Application is a continuation in part of U.S. patent application Ser. No. 08/734,861 filed Oct. 23, 1996.

FIELD OF THE INVENTION

The invention relates to stabilizer pads for vehicles, and more particularly, to an improved stabilizer pad and an apparatus for preventing a pivotally mounted, two-way stabilizer pad from reversing its orientation under its own weight.

BACKGROUND OF THE INVENTION

U.S. Pat. No. 4,889,362 discloses a reversible stabilizer pad for earth moving vehicles having a generally flanged first surface for engagement with, for example, gravel and soft earth, and a resilient surface for engagement with, for example, concrete or asphalt. This patent describes the use of rubber pads on one side of the stabilizer pad for ground contact when the vehicle is on a finished surface, such as concrete or asphalt, and flanges with grouser points on the opposite side of the stabilizer pad for ground contact when the vehicle is on an unfinished but hard ground surface that requires that the pads dig into the surface in order to better anchor and stabilize the vehicle when encountering difficult digging conditions. The flange side of the pad is unsuitable for contact with a finished surface since it could damage and/or mar the finished surface. The stabilizer pad is pivotally mounted to the end of a hydraulically operated arm such that the pad may be rotated to contact the ground with either the rubber pad side or the flange side facing down to contact the ground surface. When the vehicle is moved into a working position, if extra stability is needed, the stabilizer arms, on which the pads are mounted, are hydraulically operated to move from a retracted position, in which the arms generally extend upwardly and out of the way, to a use position, in which the arms extend downward at an angle with the pads contacting the ground surface. When the vehicle is to be moved, the arms are lifted back to the retracted position, the vehicle is moved to a new operating location and the stabilizer arms are brought down into the use position again, if necessary.

In prior stabilizer pad constructions such as the one described in U.S. Pat. No. 4,889,362, there has been a tendency for the pad to self-flip when the stabilizer arm is lifted. This self-flipping generally occurs when the flange side is down such that the stabilizer pad flips from the flange side down to the rubber pad side down. This occurs because the rubber pad side is typically much heavier than the flange side. When the pad inadvertently flips sides, an operator must manually flip the pad down so that the proper side is facing down. Frequently, however, the operator does not realize that the pad has self-flipped or, even if he/she realizes it, does not bother to fix it. When this occurs, the vehicle is used with the wrong side of the stabilizer pad in contact with the ground surface, which could result in increased hazard as well as increased wear of the rubber pads, leading to premature need for replacement. The self-flipping of the pad can be remedied with a securing or engaging bolt that is required to be secured in each position of the pad and to be disassembled and re-secured when the position of the pad is to be changed. This becomes time consuming and furthermore may involve parts that are easily lost. Further, the operator simply may not use the securing pin or bolts.

U.S. Pat. No. 4,889,362 discloses an automatically operatable latch that is adapted to rotate into an engagement with the pad when the pad is in a ground engaging surface, and is furthermore adapted to automatically rotate by gravitational force out of engagement with the pad when the arm of the earth moving machine that supports the pad is lifted. In this way, when the support arm is lifted, the latch disengages from the pad and the pad is easily rotated to its opposite position. It has been found, however, that rocks, gravel and other debris frequently get caught in the automatic latch disclosed in U.S. Pat. No. 4,889,362 which can prevent the latch from releasing when the arm is lifted. In many stabilizer constructions, the pad must rotate to some extent when the arm is lifted in order to allow the piston of the arm to retract into the cylinder. Failure of the latch to release can result in damage to the arm or pad.

In prior art stabilizer pad constructions, there is also a tendency for the pad, when configured with the rubber pad side down, to engage the ground surface with the rubber surface at an angle to the ground rather than horizontal to the ground as desired. As shown in FIG. 14, when the rubber pad engages the ground surface at an angle, it results in uneven wear of the rubber pad and causes the operator of the vehicle to be jolted as the pad shifts to engage the ground surface.

It is an object of the present invention to provide an improved stabilizer pad/arm construction for a vehicle.

It is a further object of the present invention to provide a stabilizer pad/arm construction for an earth moving machine which will not flip sides unintentionally.

It is another object of the present invention to provide a stabilizer pad having improved balance to prevent unintentional flipping of the stabilizer pad.

SUMMARY OF THE INVENTION

One embodiment of the present invention is directed to a stabilizer pad for pivotally coupling to a stabilizer arm of a vehicle such that the stabilizer pad can rotate about the stabilizer arm over a predetermined range of rotation to engage a ground surface. The stabilizer pad includes a plate having first and second ground contact faces. The stabilizer pad also includes first and second cams coupled to the plate so as to engage the stabilizer arm over at least a portion of the predetermined range of rotation to provide a resistance to rotation of the stabilizer pad with respect to the stabilizer arm.

In one version of the first embodiment of the present invention, the stabilizer pad further includes a pin that couples the stabilizer pad to the stabilizer arm. The pin is coupled to the plate using first and second bushings, and each of the first and second cams is positioned on a respective one of the first and second bushings.

In a second embodiment of the present invention, a stabilizer for stabilizing a vehicle includes a stabilizer arm, a resilient member coupled to the stabilizer arm, a stabilizer pad, a pin that pivotally couples the stabilizer pad to the stabilizer arm such that the stabilizer pad can rotate about the stabilizer arm over a predetermined range of rotation to engage a ground surface, and a first cam constructed and arranged to engage the resilient member over at least a portion of the predetermined range of rotation to provide a resistance to rotation of the stabilizer pad with respect to the stabilizer arm.

In an alternate version of the second embodiment, the stabilizer pad of the stabilizer rotates with respect to the stabilizer arm about a first rotational axis, and the resilient member is a roller pivotally coupled to the stabilizer arm such that when the cam engages the roller, the roller rotates about a second rotational axis that is parallel to the first rotational axis.

In another alternate version of the second embodiment, the stabilizer further includes a second resilient member and a second cam constructed and arranged to engage the second resilient member over at least a portion of the predetermined range of rotation to provide a resistance to rotation of the stabilizer pad with respect to the stabilizer arm.

In a third embodiment of the present invention, a stabilizer for stabilizing a vehicle includes a stabilizer arm, a stabilizer pad, a pin that pivotally couples the stabilizer pad to the stabilizer arm such that the stabilizer pad can rotate about the stabilizer arm over a predetermined range of rotation to engage a ground surface, and a first cam coupled to the stabilizer pad. The stabilizer arm includes means for contacting the first cam over at least a portion of the predetermined range of rotation to provide a resistance to rotation of the stabilizer pad with respect to the stabilizer arm.

In an alternate version of the third embodiment, the stabilizer further comprises a second cam coupled to the stabilizer pad, and the means for contacting the first cam includes means for contacting the second cam to provide a resistance to rotation of the stabilizer pad with respect to the stabilizer arm.

DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, reference is made to the drawings, which are incorporated herein by reference and in which:

FIG. 1 is a fragmentary view of a typical loader/backhoe having stabilizer pads of the prior art secured thereto;

FIG. 2 is a perspective view of the stabilizer pad and arm of FIG. 1 in a gravel or dirt engaging position;

FIG. 3 is a side elevational view of the stabilizer pad and arm construction in the position of FIG. 2;

FIG. 4 is a bottom plan view of a stabilizer pad of FIGS. 1-3 shown uncoupled from a stabilizer arm;

FIG. 5 is a sequential diagram illustrating the prior art problem of the stabilizer pad self-flipping;

FIG. 6 is a perspective view of a stabilizer pad in a ground engaging position in one embodiment of the present invention;

FIG. 7 is a side elevational view of the embodiment of the invention shown in FIG. 6;

FIG. 8 is a top plan view as seen along line 8--8 of FIG. 7;

FIG. 9 is a cross-sectional side view taken along line 9--9 of FIG. 8;

FIGS. 10-13 show a schematic cross-sectional view, similar to FIG. 9, showing the operation of a cam in accordance with one embodiment of the present invention;

FIG. 14 is a side schematic view of a stabilizer pad according to the prior art showing the pad engaging a finished surface with the surface of the pad at an angle to the ground surface;

FIG. 15 is a partially broken away side elevational view similar to FIG. 7 of a stabilizer pad in accordance with an alternate embodiment of the present invention;

FIG. 16 is a cross-sectional end view taken along line 16--16 of FIG. 15 with steel plates 122a and 122b in a horizontal alignment;

FIG. 17 is a cross-sectional view of a slotted sleeve arrangement taken along line 17--17 of FIG. 16;

FIG. 18a shows a cross-sectional view along line 18--18 of FIG. 16 with the resilient cam in an uncompressed state;

FIG. 18b is a cross-sectional view similar to FIG. 18a with the resilient cam in the first compressed state;

FIG. 18c is a cross-sectional view similar to FIG. 18a with the resilient cam in a second compressed state;

FIG. 19 is a partially broken away top plan view of another alternate embodiment of the present invention;

FIG. 20 is a cross-sectional side view taken along line 20--20 of FIG. 19;

FIG. 21 is a cross-sectional view taken along line 21--21 of FIG. 20;

FIG. 22 is an exploded perspective view of the embodiment shown in FIG. 19;

FIG. 23 is a partially broken away top plan view of another alternate embodiment of the present invention;

FIG. 24 is a cross-sectional side view taken along line 24--24 of FIG. 23;

FIGS. 25 and 26 are cross-sectional views similar to FIG. 24 showing the operation of a cam in accordance with one embodiment of the present invention;

FIG. 27 is a partially broken away top plan view of another alternate embodiment of the present invention;

FIG. 28 is a cross-sectional side view taken along line 28--28 of FIG. 27;

FIG. 29 is a partially broken away top plan view of another alternate embodiment of the present invention;

FIG. 30 is a cross-sectional side view taken along line 30--30 of FIG. 29;

FIG. 31 is a partially broken away top plan view of another alternate embodiment of the present invention; and

FIG. 32 is a cross-sectional side view taken along line 32--32 of FIG. 31.

DETAILED DESCRIPTION

FIG. 1 is a fragmentary view of a typical loader/backhoe 10 having a shovel mechanism 12, and stabilizer arms 14 and 16, each having an associated stabilizer pad 18 and 20. Each of the stabilizer arms 14 and 16 is connected to the backhoe 10 by a hydraulic piston 15 used for engaging and retracting the stabilizer arms. When the backhoe 10 is being moved, the hydraulic pistons 15 are withdrawn so that the stabilizer arms pivot and are thus elevated above ground level. In this elevated position, the stabilizer pads 18 and 20 may be rotated between a gravel position and a paved position. FIG. 1 shows the stabilizer arms 14 and 16 and the hydraulic pistons 15 in a position for engaging the ground to stabilize the backhoe 10.

The stabilizer pad 18 will be further described with reference to FIGS. 2 and 3. It should be understood that the construction of stabilizer pad 20 is substantially identical to that of stabilizer pad 18. The stabilizer pad 18 generally includes a flat plate 22 that has extending normal to the surface thereof flanges 24 and 26, both extending on one side from the surface of plate 22. The plate 22 is notched at 30 between flanges 24 and 26 and includes a cross-piece 41, as illustrated in FIG. 4. The plate is notched so as to accommodate the arm 14 and to enable the reversible rotation of the stabilizer pad 18. The stabilizer arm 14 includes a journal end for accommodating a pin 34 used to secure the stabilizer pad 18 to the arm 14. Pin 34 fits within holes 35 and 36 of flanges 24 and 26 of the stabilizer pad. The pin 34 may be secured in place by means of a typical cotter pin as illustrated in FIG. 3, or the pin 34 may be secured in place by using a bolt and nut.

The flat plate 22 has 3 laminated pads 40 mounted to a surface opposite the flanges 24 and 26. The resilient pads 40 are fixed to the flat plate 22 using bolts 53 and nuts 55. As discussed above, the side of the stabilizer pad having the resilient pads 40 is used for engaging a paved or flat surface, and the side of the stabilizer pad having the flanges 24 and 26 is for engaging a gravel or rough surface.

The weight associated with the cross piece 41 and the resilient pad 40 mounted thereto, creates an imbalance of the stabilizer pad, and thus the stabilizer pad has a tendency to flip or rotate about the pin 34. As shown in FIG. 4, counterweights 25 are added to the flange side of the flat plate 22, one on each side of the notch 30. These counterweights provide support for the flanges 24 and 26 and reduce the tendency of the pad to self-flip.

FIG. 5 illustrates a sequence of events as the stabilizer arm 14 is lifted by the backhoe 110. In the bottom position, the pad 18 is illustrated with flanges 24 and 26 in contact with a gravel surface 17. The stabilizer arm 14 may be lifted by the hydraulic piston 15 in a rather jerky motion. In the sequence shown in FIG. 5, which should be viewed from the bottom up, the pad 18 is shown engaging the ground surface 17 at the bottom of the figure. As the arm 14 is raised by the hydraulic piston 15, there is an inertia force in the direction of arrow 127 caused by the imbalance of the stabilizer pad 18, forcing the stabilizer pad to rotate about the pin 34. The same inertia force is also illustrated in the middle position of FIG. 5, wherein the pad is shown as having been half-flipped upon raising of the stabilizer arm 14. The top position in FIG. 5 illustrates the pad completely flipped to the paved surface position. If the stabilizer arm 14 is lowered again to engage the ground, the pad is oriented for engaging a paved surface, rather than oriented for engaging a gravel surface as desired because of the self-flipping that has occurred.

An operator of the backhoe 10, will typically move the backhoe many times while operating the backhoe at a job site. The movement of the backhoe requires the stabilizer arms to be retracted upwardly so that the backhoe can be moved and for the stabilizer arms to be put down again with the same side of the stabilizer pad facing down. The undesired flipping of the stabilizer pad requires the operator to manually re-flip the pad before engaging the ground surface with the pad.

If the operator does not re-flip the pad, then the resilient pads 40 may exhibit excessive wear from the uneven ground surface, and the backhoe 10 may not be properly stabilized when the resilient pads 40 are used to engage an uneven or gravel surface.

The self-flipping problem described above, generally occurs from the gravel position to the paved position of the stabilizer pad, because of the imbalance associated with the location of the resilient pad 40 and the cross piece 41. Although the counterweights 25 tend to reduce the tendency of the pad to self-flip, because of cost and weight concerns, it is undesirable to make the counterweights 25 very large, and thus, they may not effectively prevent the pad from self-flipping.

A perspective view of a two-piece stabilizer pad 118 and a stabilizer arm 114 in accordance with one embodiment of the present invention is shown in FIG. 6. The stabilizer pad 118 of FIG. 6 is similar to the stabilizer pad 18 of the prior art, except that the cross piece 41, its accompanying resilient pad 40 and counterweights 25 have been removed. The two piece stabilizer pad 118 has two steel plates 122a and 122b. Each of the steel plates 122a and 122b has a corresponding flange 124 and 126 extending on one side from the surface thereof. Each of the steel plates 122a and 122b also has laminated pads 40, similar to the stabilizer pad 18 of the prior art. Stop lugs 160a and 160b are mounted to flat plates 122a and 122b respectfully. The stop lugs prevent 360 degree rotation of the stabilizer pad 118 similar to the cross piece 41 of the prior art stabilizer pad shown in FIG. 1. The stabilizer arm 114 has a counter-clockwise stop 180 for contacting the stop lugs 160a and 160b to limit the counter clockwise rotation on the stabilizer pad. The stabilizer arm also has ears 182 that function as a clockwise stop for contacting the stop lugs to limit the clockwise rotation of the stabilizer pad.

As shown in FIG. 8, the stabilizer pad 118 mounts to the stabilizer arm 114 using a steel pin 134 similar to the stabilizer pads of the prior art. Each of the flat plates 122a and 122b of the stabilizer pad 118 has a bushing 162 welded thereon for receiving the pin 134. The steel pin 134 has a through hole at each end, and the bushing has a corresponding through hole for receiving a bolt 164. One bolt 164 along with one nut 166 is used to secure each of the flat plates 122a and 122b to the stabilizer arm, and to prevent relative rotation of flat plate 122a with respect to flat plate 122b. The embodiment of the present invention shown in FIG. 6 is lighter, less expensive to manufacture, and has improved balance over stabilizer pads of the prior art.

A self-flipping prevention feature of the stabilizer pad 118 of FIG. 6 will now be described with reference to FIGS. 6-14. As shown in FIGS. 7 and 8, pin 134 has a third through hole located approximately in the center of the pin. A cam 170 is mounted to the pin using a bolt 172, passing through the third through hole, and a nut 174. The cam 170 is generally elliptical in shape and is constructed of a resilient material such as rubber. In a preferred embodiment the cam 170 is constructed of #95A shore polyurethane.

The operation of the cam 170 will now be described with reference to FIGS. 10-13 which show the progressive counter-clockwise rotation of the stabilizer pad 118 in the direction of arrow 184 from a first position in FIG. 10 to a final position in FIG. 13. In FIG. 10, the stabilizer pad is shown with the stop lugs 160a and 160b barely out of contact with the ears 182. In this position, with the stabilizer pad rotating in the direction of arrow 184, the cam 170 is starting to come in contact with the underside of the stabilizer arm 114. In FIG. 11, the stabilizer pad is in a rotational position just beyond the gravel engaging position in the counter-clockwise direction. In the rotational position shown in FIG. 11, the cam 170 provides the maximum resistance to rotation, as the resilient cam is in a compressed state and is exerting a force on the stabilizer arm to resist further rotation. In FIGS. 12 and 13 the cam is no longer in contact with the stabilizer arm and offers no resistance to rotation of the stabilizer pad with respect to the arm, so that the arm can rotate freely. In FIG. 13, the stabilizer pad is in the smooth surface engaging position, and because the stabilizer pad is balanced, the surface of the pad is parallel to the ground surface, prior to engaging the ground. Since the pad is parallel to the ground, the stabilizer pad evenly engages the ground surface preventing excess wear and any jolting of the vehicle as in prior art stabilizer pads described above with reference to FIG. 14.

As discussed above, each of the flat plates 122a and 122b are coupled to the pin 134 using a bushing 162, a bolt 164 and a nut 166 to prevent relative rotational movement of the flat plates. In one embodiment of the present invention, as shown in FIGS. 15-17, the through holes in the bushings 162 are elongated slots 188. The slots allow some relative rotational movement between the flat plates 122a and 122b to allow the stabilizer pad to adjust to uneven ground surfaces to provide greater stability of the vehicle. Washers 167 are provided under the heads of bolts 164 and under the nuts 166 to allow easier rotation of the flat plates. Also, the ends 165 of bolts 164 are staked to prevent the nuts 166 from backing off the bolt as the flat plates are rotated in the slots 188. In a preferred embodiment, the slots allow each of the flat plates to tilt over a range of 15 degrees, thus allowing a maximum possible difference in tilt between the steel plates of 30 degrees.

The cam 170 is designed to provide sufficient rotational resistance to prevent self-flipping of the stabilizer pad, but to allow rotation of the pad when sufficient force is provided by an operator desiring to flip the stabilizer pad. In a preferred embodiment of the present invention, the resilient cam 170 has a hollow portion 192. The hollow portion 192 allows greater compression of the resilient cam to account for tolerances in the distance between the pin 134 and the underside of the arm 114. As shown in FIGS. 18a and 18b, the resilient cam offers resistance to rotation when the distance between the center of the pin 134 and the stabilizer arm 114 is equal to a first value D1 and when the distance between the center of the pin and the stabilizer arm is equal to a second value D2.

Another alternate embodiment of a stabilizer pad in accordance with the present invention will now be described with reference to FIGS. 19-22. FIG. 19 shows a partially broken away top plan view of a stabilizer pad 218 coupled to a stabilizer arm 214. The stabilizer pad 218 includes two steel plates 222a and 222b which are similar to steel plates 122a and 122b. The stabilizer pad 218 includes stop lugs 260a and 260b that prevent 360° rotation of the stabilizer pad by contacting stops 280 on the stabilizer arm 214 to prevent counter-clockwise rotation or by contacting ears 282 to limit clockwise rotation of the stabilizer pad. The steel plates 222a and 222b are connected together through a steel rod 234. Each of the steel plates is welded to the steel rod 234.

Stabilizer arm 214 has two U-shaped cutouts 290a and 290b for receiving the steel rod 234 for mounting the stabilizer pad 218 to the stabilize arm 214. The stabilizer pad is held in place in the U-shaped cutouts using retainer plates 262a and 262b which are bolted to the stabilizer arm 214 after the steel rod 234 has been placed in the U-shaped cutouts. The retainer plates are coupled to the stabilizer arm using bolts 264 and nuts 266. Two bushings 268a and 268b are mounted on the steel rod 234 between the steel plates 222a, 222b and the stabilizer arm 214. The bushings 260a and 260b are used to keep the stabilizer pad 218 centered about the longitudinal axis of the stabilizer arm 214 and to prevent steel plates 222a and 222b from contacting bolts 264.

As in the above described embodiments, stabilizer pad 218 and stabilizer arm 214 are configured to prevent self-flipping of the stabilizer pad 218. The stabilizer pad 218 includes a steel cam 270 welded to pin 234, and stabilizer arm 214 includes a resilient urethane pad 272 mounted to the underside of the stabilizer arm using bolts 274 and nuts 276. The cam 270 and the resilient pad 272 operate in a manner similar to the cam 170 of the embodiment described above with respect to FIG. 8, to prevent self-flipping of the stabilizer pad. During rotation of the stabilizer pad with respect to the stabilizer arm, the rigid cam 270 compresses the resilient pad 272. In order for further rotation of the stabilizer pad to occur, the rotational force causing rotation of the stabilizer pad must be greater than the force necessary to compress the resilient pad.

As shown in FIG. 22, in a preferred embodiment, the stabilizer pad 218 is mounted to the stabilizer arm 214 with the cam 270 rotated 180° from the resilient plate 272. This allows the stabilizer pad to be mounted to the arm 214 without compressing the resilient pad.

Another alternate embodiment of a stabilizer 300 in accordance with the present invention will now be described with reference to FIGS. 23-26. FIG. 23 shows a partially broken away top plan view of a stabilizer 300 having a stabilizer pad 318 coupled to a stabilizer arm 314. The stabilizer pad 318 includes two steel plates 322a and 322b which are similar to steel plates 122a and 122b of the stabilizer pad 118 shown in FIGS. 6-8. As in the previously described embodiments, the stabilizer pad 318 includes stop lugs 360a and 360b that prevent 360° rotation of the stabilizer pad by contacting stops 380 on the stabilizer arm 314 to prevent counter-clockwise rotation or by contacting ears 381 to limit clockwise rotation of the stabilizer pad.

The steel plates 322a and 322b are connected together through a steel pin 334 in the same manner as the steel plates 122a and 122b of the stabilizer arm 118 described above. Each of the steel plates 322a and 322b has a bushing 362 welded thereon for receiving the pin 334. The steel pin 334 has a through hole at each end, and the bushing has a corresponding through hole for receiving a bolt 364. One bolt 364 along with one nut 366 is used to secure each of the flat plates 322a and 322b to the stabilizer arm and to prevent rotation of steel plate 322a with respect to steel plate 322b.

A self-flipping prevention feature of the stabilizer 300 will now be described. The stabilizer arm 314 includes a second steel pin 372, parallel to and at a predetermined distance from the pin 334. The second steel pin has two ends, each extending through a hole 384 in the arm as shown in FIG. 23. Bushings 382 are welded to the arm and to the second pin 372 and are used to secure the second pin to the arm and to prevent the second pin 372 from rotating. Two flexible polyurethane rollers 374 are mounted on each end of the second pin.

In one embodiment, the polyurethane rollers have a hollow section having an inner diameter slightly less than the diameter of the second pin 372. The rollers are mounted on the pin by forcing the rollers onto the pin such that the diameter of the hollow section enlarges due to compression of the polyurethane material. This compression of the polyurethane material holds the rollers in place on the pin. The rollers could also be coupled to the pin using an adhesive or using nuts and bolts in a manner similar to the coupling of pin 334 to bushing 362.

A steel cam 370 is welded to each of the bushings 362 of the stabilizer pad. Each of the steel cams is of sufficient height such that with the pin 334 and the second pin 372 separated by the predetermined distance, each cam contacts one of the rollers 374 during rotation of the stabilizer pad 318 with respect to the stabilizer arm 314.

The cams 370 and the rollers 374 operate in a manner similar to cam 270 and resilient pad 272 of the embodiment shown in FIG. 19 to prevent self-flipping of the stabilizer pad 318. FIGS. 24-26 show the stabilizer pad 318 and the stabilizer arm 314 in three different relative rotational positions during rotation of the pad 318 during counter-clockwise rotation of the pad as indicated by arrow 390. As indicated by arrow 392, the cams 370 rotate about the axis of pin 334 in the same rotational direction as the pad. The steel cams compress the rollers 374, as shown in FIG. 25, to allow rotation of the pad 318. The rotational force used to rotate the pad 318 must be greater than the force needed to compress the rollers 374 for the pad to rotate from the position shown in FIG. 24 to the position shown in FIG. 26. The amount of force necessary to rotate the cams past the rollers may be adjusted by changing the predetermined distance between the pin 334 and the pin 372 or by changing the diameter of either the cams 370 or the rollers 374. Thus, the force can be adjusted to prevent self-flipping of the pad 318, and to allow intentional flipping of the pad when desired.

In an alternate version of the embodiment shown in FIG. 22, the rollers 374 rotate in an opposite direction from the rotation of the stabilizer pad when contacted by the steel cam. The rotation of the rollers is achieved by either allowing the second pin 372 to rotate freely in the holes 384 or by increasing the inner diameter of the rollers so that the rollers rotate with respect to the second pin 372. In the embodiments in which the rollers are allowed to rotate, there is less friction between the cam and the roller during compression of the roller, thereby decreasing wear of the roller. Further, since the rollers can be rotated, the cams do not always contact the same portions of the rollers, further reducing the wear of the rollers.

In the embodiment of the invention described above with reference to FIGS. 23-26, a cam 370 and a roller 374 is provided on each side of the arm 314. As understood by those skilled in the art, only one cam and one roller could be used. If only one cam and one roller is used, then the pin 372 is not necessary, and the roller 374 may be attached to the arm using an adhesive, a nut and bolt, or some other mechanism as known in the art.

Another alternate embodiment of a stabilizer 400 incorporating a self-flipping prevention feature in accordance with the present invention will now be described with reference to FIGS. 27 and 28.

FIG. 28 shows a partially broken away top plan view of a stabilizer 400 having a stabilizer pad 418 coupled to a stabilizer arm 414. The stabilizer pad 418 includes two steel plates 422a and 422b which are similar to steel plates 122a and 122b of the stabilizer pad 118 shown in FIGS. 6-8. As in the previously described embodiments, the stabilizer pad 418 includes stop lugs 460a and 460b that prevent 360° rotation of the stabilizer pad by contacting stops 480 on the stabilizer arm 414 to prevent counterclockwise rotation or by contacting ears 482 to limit clockwise rotation of the stabilizer pad. The steel plates 422a and 422b are connected together through a steel pin 434 in the same manner as the steel plates 122a and 122b of the stabilizer arm 118 described above. The self-flipping prevention feature of the stabilizer 400 will now be described. The self flipping prevention feature of this embodiment is similar to the self-flipping prevention feature of the embodiment described above with reference to FIG. 23. In the embodiment shown in FIG. 27, a polyurethane roller 474 is mounted to each of steel plates 422a and 422b, and steel cams 470 are mounted on opposite sides of the arm 414 and positioned such that the polyurethane rollers contact the cams when the stabilizer pad 418 is rotated with respect to the arm 414.

In one embodiment, the polyurethane rollers 474 are secured inside walls 424a and 424b to steel plates 422a and 422b using pins 472 which are welded to holes in the inside walls of the steel plates. The polyurethane rollers have a hollow section having an inner diameter slightly less than the outer diameter of the pins 472. The polyurethane rollers are mounted on the pins by forcing the rollers onto the pins such that the diameter of the hollow section enlarges due to compression of the polyurethane material. The rollers could also be coupled to the pins using adhesive or nuts and bolts. Cams 470 and the rollers 474 operate in a manner similar to the cams 370 and rollers 374 of the previously described embodiment of the present invention.

FIG. 28 shows compression of one of the polyurethane rollers 474 as the stabilizer pad 418 is rotated about the stabilizer arm in the direction shown by arrow 419. As shown in FIG. 28, the polyurethane roller 474 moves in the direction of arrow 492 when the pad is rotated in the direction shown by arrow 490. The steel cam 470 compress the roller 474 during rotation of the pad, as shown in FIG. 28. The rotational force used to rotate the pad 418 must be greater than the force needed to compress the rollers 474 for the pad to rotate, for example, from the paved surface position to the gravel surface position. As in the previous embodiment, the amount of force necessary to rotate the rollers past the cams may be adjusted by changing the position of either the cams or the polyurethane rollers, thereby adjusting the amount of compression of the rollers required to rotate the pad.

In an alternate version of the embodiment shown in FIGS. 27 and 28, the rollers 474 rotate in an opposite direction from the rotation of the stabilizer pad when contacted by the steel cams. This rotation is indicated by arrow 494 in FIG. 28. The rotation of the rollers is achieved by providing a rotational coupling between the pins and the steel plates so that the pins rotate with respect to the steel plates, or by increasing the inner diameter of the polyurethane rollers, so that the rollers rotate with respect to the pins. When the rollers are allowed to rotate, there is less friction between the cams and the rollers during compression of the rollers, thereby decreasing wear of the rollers. Further, since the rollers can be rotated, the cams do not always necessarily contact the same portion of the rollers, further reducing the wear of the rollers.

As understood by those skilled in the art, only one cam and one roller could be used, rather than two cams and two rollers, as shown in FIG. 27.

Another embodiment of a stabilizer 500 incorporating a self-flipping prevention feature in accordance with the present invention will now be described with reference to FIGS. 29 and 30. Stabilizer 500 has a stabilizer pad 518 that is similar to the one-piece stabilizer 30 shown in FIG. 4, however, the self-flipping prevention feature shown in FIG. 29 may also be used with the two-piece stabilizer pads shown in previously described embodiments. Stabilizer pad 518 is mounted to a stabilizer arm 514 using a pin 534 to allow rotation of the stabilizer pad with respect to the stabilizer arm in a manner similar to that described above for the prior art stabilizers.

The stabilizer arm 500 includes a self-flipping prevention feature to prevent the stabilizer pad 518 from self-flipping with respect to the arm 514. The self-flipping prevention feature includes a polyurethane roller 574 mounted to an "L" bracket 573 using a pin 572. The pin 572 is welded to the "L" bracket 573, and the "L" bracket is held to the stabilizer arm 514 using two bolts 576. The bracket 573 could alternatively be welded to the arm 514. As in previously described embodiments, the polyurethane roller is press-fit onto the pin 572, so that the polyurethane roller can rotate with respect to the pin. In an alternate embodiment, the pin 572 may be rotationally coupled to the bracket 573 to allow the pin 572 to rotate with the roller 574

The operation of the roller 574 to prevent self-flipping will now be described with reference to FIG. 30. As shown in FIG. 30, the roller 574 is compressed by the stabilizer pad 518 as the stabilizer pad rotates with respect to the stabilizer arm 514 in the direction shown by arrows 490. Rotation of the stabilizer pad 518 causes roller 574 to rotate in the direction indicated by arrow 494. The rotational force used to rotate the pad 518 must be greater than the force necessary to compress the roller 574 to allow the pad to rotate. The force necessary to rotate the pad may be adjusted by altering the position of the roller 574 so that the amount of compression of the roller required to rotate the pad increases or decreases. The resistance to rotation can be further increased by adding additional polyurethane rollers 574 to multiple places on the arm.

Another embodiment of a stabilizer 600 is shown in FIGS. 31 and 32. Stabilizer 600 incorporates a self-flipping prevention feature similar to that of the embodiment described with respect to FIGS. 29 and 30. In the stabilizer 600, self-flipping of stabilizer pad 618 with respect to stabilizer arm 614 is prevented by using polyurethane rollers 674. The polyurethane rollers, 674 operate in a manner similar to the polyurethane rollers 574 of the embodiment of the invention described above with respect to FIGS. 29 and 30, except that the polyurethane rollers of the embodiment shown in FIGS. 31 and 32 are mounted to the stabilizer pad 618 instead of to the adjacent stabilizer arm 614. Polyurethane rollers 674 are mounted to sidewalls 624a and 624b adjacent opposite sides of the arm 614 of the stabilizer pad 618. Each polyurethane roller is allowed to rotated about a pin 672 and is mounted to the stabilizer pad using a bracket 675. The brackets are mounted on the side walls using nuts 676 and bolts 677. The self-flipping prevention feature of stabilizer 600 operates in a manner similar to the self-flipping prevention feature of the stabilizer pad 500 previously described by requiring comparison of the rollers to rotate the pad with respect to the arm. During rotation of the stabilizer pad 618 with respect to the stabilizer arm 614 in the direction shown by arrow 690 in FIG. 32, each of the polyurethane rollers 674 rotates in the direction shown by arrows 694.

The stabilizer 600 utilizes a one-piece stabilizer pad 16. As understood by those skilled in the art, the self-flipping prevention feature of the stabilizer pad 600 may also be used with the two-piece stabilizer pads in accordance with embodiments of the invention described above.

In the embodiment shown in FIGS. 31 and 32, two polyurethane rollers are used. As understood by those skilled in the art, only one, or more than more than two, polyurethane rollers could be used depending on the desired resistance to rotation.

Embodiments of the present invention provide a stabilizer pad/arm construction which eliminates the self-flipping problem associated with prior art stabilizer pads, and provides a stabilizer pad having improved balance over pads of the prior art, is lighter than pads of the prior art, uses less material, and thus is less costly to manufacture than pads of the prior art.

Having thus described particular embodiments of the invention, various alterations, modifications and improvements will readily occur to those skilled in the art. Such alterations, modifications and improvements as are made obvious by this disclosure are intended to be a part of this description though not expressly stated herein, and are intended to be within the spirit and scope of the invention. Accordingly, the foregoing description is by way of example only, and not limiting. The invention is limited only as defined in the following claims and equivalents thereto. 

What is claimed is:
 1. A stabilizer for stabilizing a vehicle, the stabilizer comprising:a stabilizer arm; a resilient member coupled to the stabilizer arm; a stabilizer pad; a pin that pivotally couples the stabilizer pad to the stabilizer arm such that the stabilizer pad can rotate about the stabilizer arm over a predetermined range of rotation to engage a ground surface; and a first cam, coupled to the stabilizer pad, constructed and arranged to engage the resilient member over at least a portion of the predetermined range of rotation to provide a resistance to rotation of the stabilizer pad with respect to the stabilizer arm.
 2. The stabilizer of claim 1, wherein the stabilizer pad rotates with respect to the stabilizer arm about a first rotational axis, and wherein the resilient member is a roller pivotally coupled to the stabilizer arm such that when the cam engages the roller, the roller rotates about a second rotational axis that is parallel to the first rotational axis.
 3. The stabilizer of claim 2 further comprising:a second resilient member coupled to the stabilizer arm; and a second cam, coupled to the stabilizer pad, constructed and arranged to engage the second resilient member over at least a portion of the predetermined range of rotation to provide a resistance to rotation of the stabilizer pad with respect to the stabilizer arm.
 4. The stabilizer of claim 3, wherein the second resilient member is a second roller, pivotally coupled to the stabilizer arm such that when the second cam engages the second roller, the second roller rotates about a third rotational axis that is parallel to the first rotational axis.
 5. The stabilizer of claim 4, further comprising a second pin that pivotally couples each of the first and second rollers to the stabilizer arm.
 6. The stabilizer of claim 5, wherein the first and second cams are made of a rigid material.
 7. The stabilizer of claim 6, wherein the pin is coupled to the stabilizer pad using first and second bushings, and wherein each of the first and second cams is positioned on a respective one of the first and second bushings.
 8. The stabilizer of claim 1, further comprising a second resilient member coupled to the stabilizer arm, and wherein the pin has a second rigid cam constructed and arranged to engage the second resilient member over at least a portion of the predetermined range of rotation to provide a resistance to rotation of the stabilizer pad with respect to the stabilizer arm.
 9. The stabilizer of claim 8, further comprising a second pin that couples each of the first and second rollers to the stabilizer arm.
 10. The stabilizer of claim 1 wherein the first cam is mounted on the pin and rotates with the pin.
 11. The stabilizer of claim 10 wherein the first cam is mounted eccentrically about the pin.
 12. The stabilizer of claim 1 wherein the first cam is mounted to a bushing which is affixed to the stabilizer pad.
 13. The stabilizer of claim 1 wherein the resilient member is substantially circular in cross-sectional shape.
 14. The stabilizer of claim 1 wherein the first cam compresses the resilient member over the at least a portion of the predetermined range of rotation.
 15. A stabilizer for stabilizing a vehicle, the stabilizer comprising:a stabilizer arm; a stabilizer pad; a pin that pivotally couples the stabilizer pad to the stabilizer arm such that the stabilizer pad can rotate with respect to the stabilizer arm about a first rotational axis over a predetermined range of rotation; and a resilient roller coupled to one of the stabilizer arm and the stabilizer pad to contact the other of the stabilizer arm and stabilizer pad over at least a portion of the predetermined range of rotation to provide a resistance to rotation of the stabilizer pad with respect to the stabilizer arm.
 16. The stabilizer of claim 15, wherein the resilient roller is rotationally coupled to the one of the stabilizer pad and the stabilizer arm to allow rotation of the roller about a second rotational axis that is orthogonal to the first rotational axis.
 17. The stabilizer of claim 15, wherein the resilient roller is rotationally coupled to the one of the stabilizer pad and the stabilizer arm to allow rotation of the roller about a second rotational axis that is parallel to the first rotational axis. 